The present invention relates to a surface processing apparatus and a surface processing method for a sample such as a semiconductor element and, more particularly to a surface processing apparatus and a surface processing method suitable for performing etching and film forming on a semiconductor surface using a plasma.
Apparatuses widely used for processing such as etching and film forming of a semiconductor element are apparatuses using a plasma. The present invention can be applied to such apparatuses using a plasma, but here, a conventional technology will be explained in taking an apparatus called as an ECR (electron cyclotron resonance) type among them as an example. In the apparatus of this type, the plasma is generated by a microwave in a vacuum chamber applied with a magnetic field from the external. A bias voltage is applied to a sample in order to accelerate ions incident to the sample. The apparatus is used for film deposition as well as etching.
Recent semiconductor elements are required to be processed with high accuracy as the structure of semiconductor elements becomes finer. Therefore, a new technology is also required to improve the dimensional accuracy of a masking pattern in order to process the etched material highly accurately. As a method of controlling dimensions in forming a pattern of the masking material, a technology using an anti-reflective film such as BARC (bottom anti-reflective coating) is used in order to prevent reflection of light such as ultraviolet light and to expose finely and accurately. In general, the anti-reflective film is a film made of a material which is the same organic group as a material used for the resist, and the anti-reflective film is etched by a fluorocarbon group gas or a halogen group gas mixed with oxygen, and the selective ratio of the anti-reflective film material to the masking material at processing the anti-reflective film is nearly 1. Further, edge portions of the masking pattern are apt to be cut down by sputtering at the etching, which is a trouble at processing the base etched material. (Refer to FIG. 3(b))